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(No Model.) 2 Sheets-Sheet 1.

' E.'T, GILLILAN-D.

TELEPHONE.

No. 343,449. Patented Jun a, 1886 Inventor. $54414 Wimassaj.

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(No Model.) .2 Sheets-Sheet 2,

E. T GILLILAND.

TELEPHONE.

No. 343,449.. I Patented June 8, 18-86.

WifiZ/GJJGJ. Inventor Fhnwlilhographer. Wuhillginn. n. c.

, UNITED STATES PATENT OFFICE.

EZRA TORBANCE GILLILAND, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE AMERICAN BELL TELEPHONE COMPANY, OF SAME PLACE.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 343,449, dated June 8, 1886.

Application filed September 14, ISSS. Serial No. 177,062. (No model.)

To to whom it may concern:

Be it known that I, EZRA TORRANOE GIL- LILAND, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain Improvements in Telephones, of which the following is a specification.

My present invention has reference to that class of speaking-telephones commonly known as magneto-receivers, (although capable for use also as transmitters,) which comprise a vibratory diaphragm, and an exciting-magnet with a spool or bobbin of insulated wire adapted for inclusion in an electric circuit fixed upon one or more poles of said magnet. It constitutes an improvement and modification of the ordinary and widely-known Bell receiving-telephone, and its object is to intensify the magnetic moment of the instrument, to simplify the construction, to make a more economical instrument, to produce an instrument which shall not be susceptible to changes in temperature and climatic conditions, and, finally, to produce an instrument which requires no adj ustment, and which is in every respect strong and efficient.

For the achievement of these most desirable results, my invention consists in the employment of an iron core, in mechanical and magnetical connection with the upper or coil-inclosing portion of the telephone-case, both core and inclosing-cup being made of magnetizable metal, the latter being preferably cast-iron and magnetized'by any of the ordinary and Well-understood modes.

It also consists in making the said coil-inclosing portion of the case of cast-iron, it having been ascertained that that condition or By using a similar metallic substance for both cup and core, I avoid all risk of variation of distance between diaphragm and core under the influence of change in temperature which,with the ordinary hardrubber case, is in practice a very grave defect.

It further consists in inclosing all the screwterminals of the instrument in the helix-holding cup; in providing a third screw-terminal by which a separate strand of the mechanical fabric of the flexible cord may be held to take the strain from the conductors thereof; in bringing the ends of the telephone coil or helix to a pair of fixed metal terminal pieces, and in providing the screw terminals with contactsprings adapted to bear firmly upon the terminal pieces of the coil.

In the'drawings which form a part of this specification, Figure 1 is a front elevation of my improved telephone with the diaphragm removed to show the arrangement of the parts. Fig. 2 is a sectional side elevation of the same. Fig. 3 is an elevation of the head of the telephone,showing the spring-contacts, the metal inclosing-cup being in section. Fig. 4 is an elevation of my telephone in which the ear-piece, instead of being at right angles to the longitudinal axis of the telephone, is inline therewith. Fig. 5 is a sectional elevation, and Fig. 6 is a front plan of my improved telephone with cup and diaphragm removed made in portable form for attachment to the head-gear of operators. I

Referring to the drawings, l3 is the magnet- Y ized cast-iron inclosing-cup, and j is the softiron core,which, as shown, is screwed into the center of the base of said cup,by which it also is maintained in a magnetic state, and projects parallel to the walls thereof outwardly. The said walls extend outwardly a short distance beyond the extreme end of the core, so that when the diaphragm d is laid upon the edges of said walls, its center will be in close proximity to said core, but will not be in contact therewith.

The edge of the cup B is threaded externally, and a cap, A, of ordinary form and made of any suitable material,is adapted to be screwed thereon so asto constitute an ear-piece, and,

moreover,to hold the daphragm in place in. a

manner well understood. A circular disk, (3, of hard rubber, vulcanized fiber, or any suitable non-conducting material is perforated centrally, so as to lie in the bottom of the metal case or cup B, and to allow the central core to pass therethrough. Fixed upon this disk in such a manner as to be insulated from the metal case are two sereW-psts,eand f, and from the base of these screw-terminals contactspringsa andb ofbrass, steel, phosphor bronze, or like resilient metal or alloy, project, being madeofan approximately-oircularform,soasto be conveniently arranged within the inclosingcase. The coil or helix 0 of insulated wire is, as usual, placed on and surrounding the core j. and its two ends, in place of extending through the handle of the telephone to external screw-posts, are fastened to a pair of metal pins,h and i,which are mechanically afconducting disk 0 of a washer or nut, Z. The

spool may readily be detached from the core and contact-springs at any time for repairs or examination,by slipping it round until one of the pins (say h) is brought from under the spring a,then pressing the same spring down,

' so that the pin 1) overrides it, and turning the spool oppositely until the second pin, t, is released from the spring b.

Integral with the iron cup B and extending as a neck therefrom at right angles to the face of the ear-piece is a socket, E, threaded internally so as toserve as a sleeve for the reception of thehandle D,the latter being made of wood or of any similar non-conductor.

The handle D has a projecting ring. D, by which the instrument may be hung in the yoke of a telephone-switch; or, if preferred, a ring may be attached to either end of the instru' ment, by which it maybe hung on a hook. The handle is perforated throughout its length, and the longitudinal channel F flares into a bell'formed muzzle at the extremity of the handle.

The channel F opens into the cup of the telephone and the flexible conducting-cord G passes through it, so that the two wires 6 and f of said cord may connect with thescrew-terminal posts of the coil, thus enabling the said coil or helix to be united to any electric circuit, while a separate strand, g, of woven material, usually made of one piece of the pro tective covering of the cord, is screwed into and held by a third screw-post, g, standing between the binding-post e andf, which post though not an electric connection, is, like the others, attached to the non conducting disk 0.

The advantages I gain by inclosing the screw posts within the case, and by providing the third to support the cord are the following: In the ordinary form wherein the screw-posts are placed externally at the end of the instrnment, the person using the telephone is liable from accidental or cross currents to receive a severe shock if his fingers happen to touch the metal screw-post. When they are inclosed, this danger is avoided. The durability of the conducting-cords is greatly increased by the addition of the third screw-post, which, holding a strand of the woven fabric of the cord, takes the strain completely away from the conductors. By flaring the outer end of the telephone-handle channel I also aid in extending the life of the conducting-cord by exempting it from the abrasion which would ensue were the edge square or sharp.

By forming the spool-holding cup of magnetic material by magnetizing the same, (as I do in practice by any of the methods familiar to those skilled in the art,) and by causing the edges of the same to serve as the diaphragmseat, I not only concentrate the magnetic field so that the magnet-core is enabled to exercise a much stronger effect on the diaphragm than would otherwise be the case, but I also render the diaphragm in a measure magnetic, with a polarity opposing, and hence complementary to that of the core.

Another advantage accruing from the use of a metal inclosing-case and diaphragm'seat, is that no unequal expansion or variation of distance between the coil and core and the diaphragm can arise from variations in temperature, whereas as great a variation in distance as sixty per cent. frequently occurs when a hardrubber case is employed. By forming the inclosing-case head of cast-iron I am enabled to produce the required shape or figure readily and at reasonable cost.

I have already stated the advantage of my plan of mounting the coils-i. 6., facility and readiness of attachment and detachment.

In Fig. 4 I show a form in which the iron ICC case-head B is attachedin the same longitudinal axis as the handle of the instrument, and for some purposes this form would be preferred. In other respects the construction is identical with the form hereinbefore described.

Figs. 5 and 6 show a form of portable telephone which may by means of a suitable cap or spring attachment be worn on the head. B is the cast-iron case, and j the iron core screwed to the internal center thereof. The case and core are both magnetized, and the core will retain the magnetism by contact with the case, which remains permanently magnetic. c is the helix of wire, which surrounds the core and which terminates in the bindingscrews 6 and f, these being fixed in the substance of the cast-iron cup B, albeit insulated therefrom. A diaphragm of iron or steel rests on the circumferential edge of the case B, so that its center is opposite and close to but not in contact with the end of the core or polepiece j. The diaphragm is held in position by the cap A, which is screwed down thereon, serving also as an ear-piece for the telephone. Fig. 6 indicates the appearance of the front of this telephone, the diaphragm and cap being removed, B showing the edge of the case, 0 the coil, 6 and f the screw-connections, and j the core. a

I am well aware that it is not broadly new A to use an iron case foratelephone-magnet-and to magnetize the diaphragm inductively thereby, thisconstruction having been embodied in one of the earliest of the speaking-telephone receivers of Alexander Graham Bell, which form has become widely known under the title of the Centennial Receiver. I am also aware that it is notnew, per se, to connect the flexible conductor with the magnet-coil within thebody of theinstrument, and I do not broadly claim these details; but

'What I do claim, and desire to secure by Letters Patent, is

1. In a magneto-telephone, the combination of a permanently-magnetic cast-iron inclosingcase, a core or pole-piece metallically attached thereto and in magnetic connection therewith, so that the edge of the said case constitutes one pole of the magnet and the said core the other, and a diaphragm resting on the edge of the. said case.

2. In a telephone,acircular magnetized castiron inclosing case or cup, acore or pole-piece of iron attached to the internal surface of the base of said cup, and maintained in a magnetic condition by virtue of attachment, a diaphragm resting on theedge of said cup, the said edge being extended outwardly beyond the end of the core sufficiently to enable the center of the diaphragm to be close to said core without touching the same, acoil or helix of insulated wire adapted to be included in an electric circuit surrounding the said polepiece within the said magnetic inclosing-case, and a cap capable of being screwed down on the case to hold the diaphragm in place, and toserve as an ear-piece, substantially as described.

3'. In atelephone, the combination of the metal inclosing-case, ahollow handle therefor attached thereto, as described, an insulatingdisk attached to the floor of said case, a-pair of binding-screw posts secured to said disk for the attachment of the electric connections of a flexible conductor, and a third binding-screw attachment similarly mounted, and adapted to be connected with a non-conducting strand of the said flexible cord, so as to relieve thestrain upon the electric conductors thereof, substantiall y as described.

4. In a telephone, a permanently-magnetic case, adapted to contain the operative parts and to serve as a seat for the diaphragm, an iron core deriving its magnetism from the said case and constituting a central pole there for, and a wire coil surrounding said central pole, and connected by contact-springs with screw-terminals, whereby the said coil may be included in an electric circuit.

5. In a magneto-telephone, a detachable 1nducing coil or helix, complete in itself, and adaptedby means of terminal pins affixed to the edge of the bobbin on which the said helix 'is 'wound to engage and lock with contactsprings connected with or adapted to be connected with an electric circuit, as and for the purposes described.

6. In an electric telephone, a magnet, and an iron core or pole-piece therefor, a coil or helix of insulated wire surrounding the sa1d core, binding-screws for connection with an electric circuit, and spring-connectlons extending between the said bindingscrews and the coil-terminals, the said springs belng permanently secured to the former and adapted to make contact with the latter by the resiliency of their free ends, whereby the 0011 may be readily attached for use, or detached for inspection or repairs.

7. In' a magneto-telephone, the followlng elements in combination: a magnetlzed castiron inclosing cup or case, a core or pole-piece attached to and projecting from the center of the floor of said cup and magnetized therefrom, a pair of screw-connections attached to a non-conducting disk (which disk 1S per nanently attached to the floor of the inclos ngcase) and adapted to connect by suitable wires with an electric circuit, a metal spring attached to each screw-connection and extending therefrom within the case, and a helix of insulated wire, the spool of which is adapted to slide easily over the pole-piece, and is likewise provided with rigid metal pins constituting the terminals of the helix, which pins are adapted when the helix is slid on the core to be turned round, and to be brought under and into electrical contact with the free ends of the metal springs, or to be reversely detached therefrom, in the manner and for the purposes descrlbed.

8. A magneto-telephone comprising the following elements: a circular magnetized castiron case, an iron core or pole-piece pro ectmg from the interior center of the floor thereof, a vibratory diaphragm resting by its edges on the edge of the case and having ts center n close proximity to but not in contact with the core, a helix or coil surrounding the sa1d core, a non conducting disk or washer mounted upon the interior surface of the floor of the inclosing-case, a pair of binding-posts mounted on said disk, and adaptedfor connectlon with the electrical conducting-strands of a flexible conducting-cord, a single'binding-post adapted to hold a non-conducting strand of sa1d cord, spring-connections between the two electrical binding-screws and the coil-terminals, a hollow handle opening into the case, whereby a flexible conductor is conveyed to the b1nding-screws, and an ear-piece or cap, all arranged asdcscribed, and for the purposes set forth.

IIO

9. The combination, in a telephone, of the In testimony whereof I have signed my name 10 magnetized iron ease or head 13, provided to this speoification,in the presence of two subwith a threaded and perforated shoulder, E, scribing witnesses, this 25th day of August, ul lith the non-conducting perforated handle D, i 1885.

t e said handle having a collar D by which r V it may be suitably supported i n a yoke, and EZRA EORRANOD GILLTLAND' having a flaring or bell-shaped expansion to YVitnesses:

the channel at its outer end or muzzle, sub- GEO. W'ILLIS PIERCE,

stantially as and for the purposes described. GEO. H. E. TRoUvnLoT. 

